tm1300 NXP Semiconductors, tm1300 Datasheet - Page 430

• Manufacturer Part Number: tm1300
• Description: Tm-1300 Media Processor
• Manufacturer: NXP Semiconductors

TM1300 Data Book
pref16x
SYNTAX
[ IF r guard ] pref16x r src1 r src2
FUNCTION
DESCRIPTION
rscr2)) & cache_block_mask) and stores the data into the data cache. This operation is not guaranteed to be
executed. The prefetch unit will not execute this operation when the data to be prefetched is already in the data cache.
The data cache has hardware to simultaneously sustain two cache misses or prefetches. A pref16x operation will not
be executed when the cache is already occupied with 2 cache misses, when the operation is issued.
execution of the prefetch operation. If the LSB of rguard is 1, prefetch operation is executed; otherwise, it is not
executed
EXAMPLES
NOTE: This operation is supported only in TM1000, TM1100 and TM1300 and it is not
guaranteed to be available in future generations of Trimedia products.
A-144
r10 = 0xabcd, r12 = 0xc
cache_block_size = 0x40
r10 = 0xabcd, r11 = 0, r12=0xc,
cache_block_size = 0x40
r10 = 0xabff, r11 = 1, r12 =0x1,
cache_block_size = 0x40
The pref16x operation loads one full cache block from the main memory at the address computed by ((rsrc1+ (2 x
The pref16x operation optionally takes a guard, specified in rguard. If a guard is present, its LSB controls the
if r guard then {
}
cache_block_mask = ~(cache_block_size - 1)
data_cache <- mem[(rsrc1 + (2 x rscr2)) & cache_block_mask]
Initial Values
PRODUCT SPECIFICATION
pref16x r10 r12
IF r11 pref16x r10 r12
IF r11 pref16x r10 r12
Operation
prefetch with 16-bit scaled index
Loads a cache line for the address space from
0xabc0 to 0xabff from the main memory. If the data is
already in the cache, the operation is not executed.
since guard is false, pref16x operation is not executed
Loads a cache line for the address space from
0xac00 to 0x0xac3f from the main memory. If the
data is already in the cache, the operation is not exe-
cuted.
pref32x prefd prefr allocd
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
Philips Semiconductors
Result
allocr allocx
ATTRIBUTES
SEE ALSO
dmemspec
211
No
2
5
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